1. Field of the Invention
The present invention relates generally to radio frequency spectrum management systems, and, more particularly, to systems and methods for recovering and/or sharing radio frequency spectrum in radio frequency bands already populated by legacy users (such as cell phone users) and high-priority users (such as public safety, military and government entities) without exposing those legacy and high-priority users to harmful interference.
2. Description of the Related Art
Wireless communications network bandwidth continues to shrink at an alarming rate. Increasing demand for spectrum-based services and devices is putting a strain on long-standing and out-moded spectrum allocation and use policies. Managing interference levels among the rapidly increasing number of users has become extremely difficult because of the greater density, mobility and variability of “next generation” (XG) radio frequency emitters.
Current spectrum management policy seeks to assign locally unoccupied portions of the RF spectrum to XG users. The Federal Communications Commission (“FCC”) Spectrum Management Policy Task Force has recommended adoption of a policy of “Interference Protection,” which defines an acceptable level of interference to primary users from secondary users in terms of this interference temperature. Under the recommended policy, secondary users of a band are required to accept interference from primary users, and must cause no “harmful” interference to the primary users. Thus, the policy permits secondary (e.g., unlicensed) users to radiate only enough power in an area of interest to raise the interference temperature in the band to a specified threshold T0 for the band, service, and locality. The receivers of the primary (e.g., licensed) users are then expected to tolerate this specified level of interference. This proposed arrangement, if it is widely adopted, will create an opportunity to “underlay” existing primary applications with low-power, low-impact opportunistic applications that operate below the threshold.
While the Spectrum Policy Task Force Report recommends a new set of rules for spectrum use that in turn will provide a sound framework for using the available spectrum more efficiently, the report does not address many important and heretofore unanswered questions about how to build and configure networks and devices that comply with the new set of rules. Accordingly, what is needed are tools, devices and applications XG users can build, configure and deploy in order to take advantage of the proposed spectrum policies.